The present invention relates to a fixing system for fixing a toner image formed on a copy paper in a copying machine and, more particularly, to a control system for selecting a desired fixing temperature in accordance with the quality and the specific gravity of the copy paper being used.
In the conventional electrophotographic copying machine, a specific copy paper suited for the machine is used to ensure a clean copy. However, it is desirable to allow various kinds of copy paper to be used without deteriorating the copying quality. In the case where a copy paper of a large specific gravity is used, the fixing temperature should be raised to completely perform the fixing. In the case where a copy paper of a small specific gravity is used, the fixing temperature should be lowered to prevent the copy paper from burning.
Accordingly, an object of the present invention is to provide a novel thermal fixing system for fixing a toner image formed on a copy paper in an electrophotographic copying machine.
Another object of the present invention is to provide a fixing temperature control system for selecting a desired fixing temperature in accordance with variations of the copy paper characteristics.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, two copy switches are provided for a thick paper copy mode and a thin paper copy mode, respectively. A fixing temperature control circuit is associated with the two copy switches in order to control the operation mode of a thermal fixing system for fixing a toner image formed on a copy paper. When a thick paper copy mode switch is actuated, the fixing temperature control circuit activates the thermal fixing system to operate in a higher temperature mode. When a thin paper copy mode switch is actuated, the fixing temperature control circuit activates the thermal fixing system to operate in a lower temperature mode.